The invention relates to a method and to a device for the conveyance of workpieces, more especially in the form of circuit boards, in sequence along a conveyance path in steps.
The production of circuit boards or like articles involves their conveyance through various working stations of an automatically controlled production line. If failure of one working station occurs, the flow of material will be interupted at this point. On the other hand it is normally not possible for the supply of further material to be interrupted and it is thus necessary to temporarily store the workpieces until the failure has been dealt with. In this respect it is to be taken into account that more especially in the case of the production of circuit boards batches of identically sized boards may be comparatively small and that after each batch has run through the plant retooling is needed at each individual station, this generally being performed automatically. A change in the sequence of the series of circuit boards might thus lead to interference with the entire production process and make complex adjustments necessary. Furthermore, it is to be taken into account that inversion of the workpieces as a result of the temporary storage is undesired.
There has already been a proposal to provide a circulating element with peripherally arranged receiving compartments for the temporary storage of workpieces. However when using this device it is only possible to avoid inversion of the workpieces, if the circulating element is driven in opposite directions for storing and releasing the workpieces, this not only involving a change in the order of the workpieces but also at the same time having to hold up the supply of further workpieces. This however means that the above requirements are not fulfilled.